What happens during diastole?

During diastole, the ventricles of the heart relax and fill with blood. This phase is essential for the heart's function, as it allows the chambers to receive blood from the atria and prepare for the next contraction. During diastole, the pressure within the ventricles decreases, causing the mitral and tricuspid valves (the valves between the atria and ventricles) to open. This enables blood that has returned to the heart from the body and lungs to flow into the ventricles, setting the stage for the subsequent systole phase when the ventricles will contract and pump that blood out to the lungs and the rest of the body.

The filling of the ventricles during diastole is crucial for maintaining adequate cardiac output and ensuring that the organs receive sufficient blood supply. This process is also influenced by the volume of blood returning to the heart and the overall compliance of the ventricular walls.